| ( | 40 | − | 2 | x | ) | ( | 60 | − | 3 | x | ) | = | 600 |
| Left side of the equation = | 40 | ( | 60 | − | 3 | x | ) | − | 2 | x | ( | 60 | − | 3 | x | ) |
| = | 40 | × | 60 | − | 40 | × | 3 | x | − | 2 | x | ( | 60 | − | 3 | x | ) |
| = | 2400 | − | 120 | x | − | 2 | x | ( | 60 | − | 3 | x | ) |
| = | 2400 | − | 120 | x | − | 2 | x | × | 60 | + | 2 | x | × | 3 | x |
| = | 2400 | − | 120 | x | − | 120 | x | + | 6 | x | x |
| = | 2400 | − | 240 | x | + | 6 | x | x |
| 2400 | − | 240 | x | + | 6 | x | x | = | 600 |